Burj Dubai - "Dubai Tower"

Burj Dubai ("Dubai Tower") is a supertall skyscraper under construction in the Business Bay district of Dubai, United Arab Emirates, and is the tallest man-made structure ever built, despite being incomplete. Construction began on September 21, 2004 and is expected to be completed and ready for occupation in September 2009.

The building is part of the 2 km2 (0.8 sq mi) development called "Downtown Dubai", at the "First Interchange" (aka "Defence Roundabout") along Sheikh Zayed Road at Doha Street. The tower's architect is Adrian Smith who worked with Skidmore, Owings and Merrill (SOM) until 2006. The architecture and engineering firm SOM is in charge of the project. The primary builders are Samsung Engineering & Construction and Besix along with Arabtec. Turner Construction Company was chosen as the construction manager.

The total budget for the Burj Dubai project is about US$4.1 billion and for the entire new 'Downtown Dubai', US$20 billion. Mohamed Ali Alabbar, the CEO of Emaar Properties, speaking at the Council on Tall Buildings and Urban Habitat 8th World Congress, said that the price of office space at Burj Dubai had reached $4,000 per sq ft (over $43,000 per sq m) and that the Armani Residences, also in Burj Dubai, were selling for $3,500 per sq ft (over $37,500 per sq m).

As of September 26, 2008, Burj Dubai had reached a height of 707 m (2,320 ft).

Current records
* Tallest structure: 707 m (2,320 ft) (previously KVLY-TV mast - 628.8 m (2,063 ft))
* Tallest freestanding structure: 707 m (2,320 ft) (previously CN Tower - 553.3 m (1,815 ft))
* Building with most floors: 160 (previously Sears Tower / World Trade Center - 110)
* Highest vertical concrete pumping (for a building): 601 m (1,972 ft) (previously Taipei 101 - 449.2 m (1,474 ft)).
* Highest vertical concrete pumping (for any construction): 601 m (1,972 ft) (previously Riva del Garda Hydroelectric Power Plant - 532 m (1,745 ft).

The projected final height of Burj Dubai is officially being kept a secret due to competition from other buildings under construction or proposed; however, figures released by a contractor on the project have suggested a height of around 818 m (2,684 ft). Based on this height, the total number of habitable floors is expected to be around 162. However, Burj Dubai's construction manager, Greg Sang, has said only that the final height would be greater than 700 m (2,297 ft), a height already exceeded, and that it would be the world's tallest free-standing structure when completed.

The tower is designed by Skidmore, Owings and Merrill, who also designed the Sears Tower in Chicago and the Freedom Tower in New York City, among numerous other famous high-rises. The building resembles the bundled tube form of the Sears Tower, but is not a tube structure. The design of Burj Dubai is reminiscent of the Frank Lloyd Wright vision for The Illinois, a mile high skyscraper designed for Chicago, Illinois. Emaar has also engaged GHD, an international multidisciplinary consulting firm, to assist with the design, review and assessment involved in the construction process.

Photo by Bret Oliver

The design of Burj Dubai is derived from patterning systems embodied in Islamic architecture, with the triple-lobed footprint of the building based on an abstracted version of the flower Hymenocallis. The tower is composed of three elements arranged around a central core. As the tower rises from the flat desert base, setbacks occur at each element in an upward spiralling pattern, decreasing the cross section of the tower as it reaches toward the sky. At the top, the central core emerges and is sculpted to form a finishing spire. A Y-shaped floor plan maximizes views of the Persian Gulf. Viewed from above or from the base, the form also evokes the onion domes of Islamic architecture. During the design process, engineers rotated the building 120 degrees from its original layout to reduce stress from prevailing winds. The tower, at its tallest point, sways a total of 1.2 m (3.9 ft).

The exterior cladding of Burj Dubai will consist of 142,000 m2 (1,528,000 sq ft) of reflective glazing, and aluminium and textured stainless steel spandrel panels with vertical tubular fins. The cladding system is designed to withstand Dubai's extreme summer temperatures. Additionally, at its projected height, the exterior temperature at the top of the building will be noticeably cooler than at its base, by 6 °C (11 °F).

Photo by orbit_77

The interior will be decorated by Giorgio Armani. An Armani Hotel, the first of four by Armani, will occupy the lower 37 floors. Floors 45 through 108 will have 700 private apartments on 64 floors (which, according to the developer, sold out within eight hours of going on sale). An outdoor zero-entry swimming pool will be located on the 78th floor of the tower. Corporate offices and suites will fill most of the remaining floors, except for a 123rd floor lobby and 124th floor (about 440 m (1,444 ft)) indoor/outdoor observation deck. The spire—itself over 200 m (700 ft) tall—will hold communications equipment.

It will also feature the world's fastest elevator, rising and descending at 18 m/s (59 ft/s). The world's current fastest elevator (in the Taipei 101) travels at 16.83 m/s (55.2 ft/s). Engineers had considered installing the world's first triple-decker elevators, but the final design calls for double-deck elevators. A total of 56 elevators will be installed that can each carry 42 people at a time.

Photo by imredubai

The tower is being constructed by a South Korean company, Samsung Engineering&Construction which also built the Petronas Twin Towers and the Taipei 101. Samsung Engineering & Construction is building the tower in a joint venture with Besix from Belgium and Arabtec from UAE. Turner is the Project Manager on the main construction contract.

The primary structural system of Burj Dubai is reinforced concrete. Over 45,000 m3 (58,900 cu yd) of concrete, weighing more than 110,000 tonnes (120,000 ST/110,000 LT) were used to construct the concrete and steel foundation, which features 192 piles buried more than 50 m (164 ft) deep. When completed, Burj Dubai's construction will have used 330,000 m3 (431,600 cu yd) of concrete and 39,000 tonnes (43,000 ST/38,000 LT) of steel rebar (enough to extend over a quarter of the way around the world if laid end-to-end); and construction will have taken 22 million man hours.

As construction of the tower progresses, it becomes increasingly difficult to vertically pump the thousands of cubic metres of concrete that are required. The previous record for pumping concrete on any project was set during the extension of the Riva del Garda Hydroelectric Power Plant in Italy in 1994, when concrete was pumped to a height of 532 m (1,745 ft). Burj Dubai now holds this record as of August 19, 2007, as it has a height of 536.1 m (1,759 ft), to hold the record for concrete pumping on any project; and as of November 8, 2007 concrete was pumped to a delivery height of 601 m (1,972 ft).

Photo by daveandmairi

Special mixes of concrete are made to withstand the extreme pressures of the massive weight of the tower; as typical with reinforced concrete construction, each batch of concrete is tested and checked to see whether it can withstand certain pressures. The head of Concrete Quality Checking on the Burj Dubai project is Alam Feroze, who is in charge of concrete on the whole project. The concrete pumps, pipelines and booms are provided by Putzmeister, of Aichtal, Germany.

The consistency of the concrete on the project is essential. It was difficult to create a concrete that could withstand the thousands of tonnes bearing down on it and also withstand Gulf temperatures that can reach 50 °C (122 °F). To combat this problem, the concrete is not poured during the day. Instead, ice is added to the mixture and it is poured at night when it is cooler and the humidity is higher. A cooler concrete mixture cures evenly throughout and therefore is less likely to set too quickly and crack. Any significant cracks could put the whole project in jeopardy.

Photo by orbit_77

Photo by cdiclerico